Transfer of embryos with segmental mosaicism is associated with a significant reduction in live-birth rate.

OBJECTIVE

To evaluate the impact of segmental mosaicism on pregnancy outcomes from the transfer of embryos previously designated as euploid.

DESIGN

Retrospective cohort analysis.

SETTING

Single, private, high-volume fertility center.

PATIENT(S): Three hundred and twenty-seven women who underwent 377 frozen single euploid embryo transfers.

INTERVENTION(S): Trophectoderm biopsy of embryos cultured to the blastocyst stage, where all transferred embryos were designated euploid by high-density oligonucleotide array comparative genomic hybridization (aCGH); after ascertaining all outcomes, revaluation of aCGH results for evidence of segmental mosaicism (defined as mosaicism on a portion of a chromosome).

MAIN OUTCOME MEASURE(S): Live-birth rate and spontaneous abortion rate.

RESULT(S): Of the 377 embryos transferred, 357 were euploid with no mosaicism, and 20 embryos had segmental mosaicism. Segmental mosaics had a statistically significantly lower live-birth rate compared with euploid controls (30.0% vs. 53.8%). When controlling for age and day of Trophectoderm biopsy, the odds for live birth after transfer of segmental mosaics were reduced by 66% compared with euploid controls (0.34; 95% confidence interval, 0.13-0.92). The spontaneous abortion rate was statistically significantly higher after transfer of segmental mosaics compared with euploid controls (40.0% vs. 18.2%).

CONCLUSION(S): Blastocysts with segmental mosaicism have reduced reproductive potential but retain the ability to result in live birth. These results support reporting segmental mosaicism to optimize selection of a single embryo for transfer that will maximize the chance of life birth.